Valve.



N0. 889,895. PATENTED JUNE 9, 1908.

F. G. BLANCHARD & P. G. DARLING.

VALVE.

APPLICATION FILED NOV. 9. 1901.

\X/IT' 55555: i \/5 PUP-K5 adii a a T D sT Es PATENT OFFICE.

' FREDERICK c. BLANCHARD AND PHILIP G. DARLING, OF, BRIDGEPORT, CONNECTICUT, ASSIGNORS TO THE CONSOLIDATED SAFETY CONNECTICUT, A CORPORATION OF CONNECTIOU VALVE COMPANY, or BRIDGEPORT,

VALVE No. ceases.

Patented June 9, 1908.

Application filed November 9, 1907. Serial No. 401,469.

To all whom it may concern:

Be it known that we, FREDERICK O. BLANCHARD and PHILIP G. DARLING, citizens of the United States, and residents of- 5 Bridgeport, in the county of Fairfield and State of Connecticut, have invented new and useful Improvements in Valves, of which the following is a specification.

Our invention relates to safety valves such as are used on steam boilers and its object is to eliminate back pressure on the valve.

As is well known, a safety valve must be set so as to be sensitive to even slight changes in the pressure of the steam and consequently, if, on the opening of the valve, any back pressure is added to the pressure of the spring b which the valve is set, the accurate wor ing of the valve is seriously interfered with. The older types of safet valves are commonly constructed with a cy indrical flange or sleeve which fits inside the skirt of the spring casing and is in sliding contact therewith, the latter having also a-circumferential shoulder or ledge ro'ecting into the steam passage through w iich the steam exhausts from the valve. In this construction the steam not only exerts back pressure upon the annular ledge of the valve but too readily leaks into the spring casing through the joint formed by the sliding flange and the skirt of the spring casing and there exerts back pressureon the main body of the valve itself. If, when the valve has popped, back pressure is develo ed on the valve, it will chatter opening am closing a number of times in rapid succession, thus interferlng with 1ts efficiency and ln uriously wearing the parts. Back pressure on the valve also tends to hold the valve down and reduce the opening of the valve and conse-' quentl its relieving capacity.

In t 1e drawing A represents a safety valvecasing, provided with a valve seat in which the valve B is seated; C is a spring casing 4 having an annular skirt 0 projecting toward the valve; and containing a spring D which holds the valve B. on its seat in the usual manner F is tlfe outer 'dependin portion of the s ring casing mounted on sai valve casing; is the muffler hood which may, if desired, be mounted on the flange of the spring casing; H is a steam passage I is an inlet through which steam passes from the valve casing or to the muffler, and J is the adjusting ring. The feather head consisting of the c lindrical flange E which is comparatively t iin projects into the steam passage H and is in sliding connection with and fits outside of the annular skirt C of the spring casing C and extends a ong said annular skirt for a, considerable distance. 0 is sometimes grooved and a packing or piston ring inserted to keep this joint reasonabl tight without undue sliding friction. T e adjusting ring J is provided with an annular 5 rim extending u ward into the steam passage H and in e ect forming with the cylindrical flange E an annular flaring nozzle into and through which the steam asses from the huddlin chamber. Preferal fl the side 7 of this nozz e is conical in form as shown in the drawing, but it may be made in other forms without departing from our invention provided the shape of the orifice enables it to perform the well known functions of the expanding delivery nozzle of the Venturi tube. As a result of this construction the area of the feather head E at the top on which steam can exert back pressure 1s so small that no a lpreciable pressure is ex- 0 erted upon it. 'F e steam in its rush u ward from the flaring orifice formed by t e upwardly extending rim of the adjusting ring and the upwardly extending flange E, clears itself with a minimum of eddy-making and s5 flows freely along the wall of the said cylindrical flange E, and the rush of steam u ward past the comparatively thin feather head is sufficient to prevent any steam from being forced down between the feather head and the skirt of the spring easing into the spring casing itself and there exerting back pressure on the valve.

The behavior of safety valves, constructed as above described, indicates that the condition in the steam esca e passage around and near the feather head is similar to that in steam injector tubes at points whre the velocity and changing cross section of the steam jetare such that no lateral pressure is exerted on thejsides of the tube, or such that free apertures in the tube perform the function of intake passages, showing that the internal condition at that point is tending toward a vacuum. In the safety valve, above described, observation fails to detect any tendency of steam to escape through the joint between the feather head and skirt into the spring chamber and we are inclined to believe that the pressure conditions at the juncture of the feather head with the skirt tend I free flow of steam after it leaves the valve rather to draw air from the spring chamber than to force steam mto it. The joint between the feather head and the' annular' skirt of the spring caslng is practicall steam tight, although sufliciently free to al ow the feather head to slide readily. I

Another advantage of our invention is that in the older types of safety valves there is more back pressure when a muffler is used than there is without a muflier and therefore the valve must be adjusted differently or a differently cut adjustmg ring must be used according as the valve is used with or without a muffler. In our invention, on the contrary, the bad effects of back pressure being eliminated, there need be but one adjustment of the valve regardless of its use with or without a muffler; this advanta e results in saving of time and trouble and in cost of manufacture.

What we claim and desire to secure by Letters Patent is:

1. In a safety valve, a valve casing provided with a valve seat, a valve cooperating with said valve seat, a spring casing having an annular skirt projecting toward sald valve, said valve having a flange outside of and in sliding engagement with said annular skirt, an adjusting ring surrounding and adjacent to the outer lip of the valve, and provided with a rim extending upwardly beyond the lower end of the flange of said valve, the flange and rim constituting a flarin nozzle to facilitate free flow of steam after 1t leaves the valve seat, and means to set said adjusting ring in an determined position.

2. In a sa ety valve, a valve casing provided with a valve seat, a valve cooperatin with said valve seat, a spring casing mounte on said valve casing, a muflier mounted on said spring casing, said spring casing having an annular skirt projecting toward said valve and said valve having a flan e outside of and in sliding engagement wit said annular skirt, an adjusting ring surrounding and adj acent to the outer lip of the flange and provided with a rim extendin beyond the lower end of the flange of said va ve, the flange and rim constituting a flaring nozzle to facilitate seat, and means to set said adjusting ring in any determined position.

3. In a safety valve, a valve casing provided with a valve seat, a spring-operated valve cooperating with said valve seat, a sprin cas1ng,'m0unted on said valve casing, a muffler mounted on said s rin' casing said spring casing having an annu ar s irt projectin toward said valve and said valve having a ange outside of and in sliding engagement with said annular skirt, the outer surface of said flange being a e lindrical extension substantially equal in iameter to the extreme outer portion of said valve, an adjusting ring surrounding and adjacent to the outer lip of the valve and provided with a rim extending upwardly be 0nd the lower end of the flange of said va ve, the flange and rim constituting a flaring nozzle to facilitate free flow of steam after it leaves the valve seat, and means to set said adjusting ring in any determined position.

4. In a safety valve, a valve casing provided with a valve seat, a valve cooperating with said valve seat, a spring casing mounted on said valve casing and havin an annular skirt projecting toward said va ve, a muffler mounted on said spring casin steam passa es between the outer depeniflng wall and t 1e annular skirt of said spring casing, passages from said steam assage to said muffler, said valve having a ange projectin into said steam passage and outside of am in sliding engagement with said annular skirt, an adjusting ring surrounding and adjacent to the outer lip of the valve and provided with a rim extending u wardly beyond the lower end of the flange of said valve, the flange and rim constitutmg a flaring nozzle to facilitate free flow of steam after 1t leaves the valve seat, and means to set said adjusting ring in any determined position.

Signed by us at Bridgeport, Conn, this sixth da of November 1907.

flREDERICK O. BLANCHARD. PHILIP G. DARLING. Witnesses: W. R. CLARKE, ERNEST B. CRooKEIe 

